Vacuum cleaner



June 29, 1937. G. E. LOFGREN VACUUM CLEANER Filed June 12, 1955 Patented .lune 29, 1937 @with VACUUM CLEANER Gustaf Einar Lofgren, Riverside, Conn., assigner to Electrolux Corporation, Dover, Del., acorporation of Delaware Application June 12,

4 CIaims.

My invention relates to vacuum cleaners and more particularly to vacuum cleaners of the enclosed bag type. In Vacuum cleaners of this type a casing is provided for enclosing a dust bag and a motor-fan unit. This casing is provided with an opening through which the bag may be removed in order to empty dust which, has accumulated therein. It is advantageous to make the bag of greater length than the length of lo the space in the Casing in which it is received in order to increase the surface area of the bag.

This, of course, results in the sides of the bag being folded or wrinkled when within the casing.

If the casing is adapted to be supported in a horizontal position on a horizontal surface, the dust bag opening is conveniently placed at one end of the casing. It is advantageous to have this opening located in a plane inclined with respect to the lengthwise extent of the space in order that, when the cover closing the opening is removed, the dust within the bag will not have a tendency to fall out. A vacuum cleaner constructed in this manner is disclosed in my copending application Serial No. 10,620, and the advantages resulting therefrom are therein set forth in detail.

I have found that with a cylindrical bag of greater length than the space in which it is received, some diiculty may be experienced in properly inserting the bag in the casing In Aorder to insert the bag, it is convenient to start the motor-fan unit, and the flow of air thereby produced through the casing serves to inate the bag and draw it into the casing until the rear or closed end of the bag contacts the wall I defining the rear of the space. In this position,

a portion of the front of the bag extends outside the casingand, when this part is forced into the space, the walls of the bag fold or wrinkle adjacent to the mouth and there is little or no tendency for these folds to be moved toward the rear.

The above diculty occurs whether the dust bag opening is in a vertical or inclined plane. In addition, if the opening is in an inclined plane, when the inated and straightened bag is inserted through the inclined opening, the lower part of the rear or closed end of the bag bears against the bottom of the casing. The result is that the bag may not be drawn to its proper position, and the" bag may remain in a wrinkled condition adjacent to the opening. This not only causes dust to collect adjacent to the mouth of the bag, but if the vacuum cleaner is provided 1935, Serial No. 26,110

with dust-indicating apparatus which depends upon the exertion of pressure by the end of the bag against a movable plate, the dust indicator may not function properly.

One of the objects of my invention is to provide a bag longer than the space in which it is adapted to be received and of such form or shape that the wrinkles or folds resulting from its excess length will be distributed more toward the closed end of the bag and away from its mouth.

Another object of my invention is to provide a dust bag of such form or shape that it may be readily inserted through an inclined opening and when so inserted the closed end of the bag does not bear against the bottom of the casing to such an extent that it cannot move to its proper location.

Further objects and advantages of my invention will be apparent from the following description considered in connection with the accompanying drawing, which forms a part of this specification, and of which:

Fig. 1 is a side View, chiefly in cross-section, of a vacuum cleaner including an embodiment of my invention;

Fig. 2. is a cross-sectional View taken on the line 2-2 of Fig. 1;

Fig. 3 is a cross-sectional View on an enlarged scale of a detail of the construction shown in Fig. 1; and

Fig. 4 shows on reduced scale a piece of material cut to form the curved side of the dust bag before the edges of the material have been secured together.

Referring now more particularly to Fig. 1, reference character I0 designates a casing which may be cylindrical or of any other desired shape. The left-hand end, as Viewed in Fig. 1, of casing I0 terminates in a plane inclined to the vertical. A ring II is suitably secured to this inclined end of the casing. A dust bag ring I2 is formed with an annular flange I3 and a packing ring I4 of rubber or other suitable material is supported on the flange. A. closure member I5 is adapted to be removably secured in place on ring I I in any suitable manner as by spring clips I6. Flange I3 carrying packing ring I4 is adapted to be clamped between closure member I5 and rngII. Closure member I5 is provided with a central opening I1 which may be screw-threaded so as to receive a coupling I8. Coupling I8 is adapted to ,receive one end of a flexible hose I9, to the other end of which may be connected a suction nozzle 20. A rigid handle member 2| may be interposed between nozzle 20 and hose I9.

Secured to dust bag ring l2 is a dust bag 22 `made of suitable exible material such as cloth,

which permits the passage therethrough of air while being substantially impervious with respect to dust. Bag 22 may be made by cutting a piece of cloth to the shape shown in Fig.' 4, that is, with sides tapering from each end toward an intermediate point 23. Point 23 is preferably closer to one end of the piece of the material than it is to the other. The ends 23 and 25 of the cloth are preferably cut in .an arc, so that, when side edges 26 and 2 are secured together, the ends of the bag will be straight. Edges 2E andv 2l are preferably secured together by sewing, and a circular piece of material is sewed tothe end 25 so as to provide a substantially iat closed end for the bag. When the bag is placed with the seam 28 made by sewing edges 23 and 2l together as aforesaid, at the top, the bag will take a position as shown in Fig. 1, that is, ii the closed end of the bag is in a vertical plane, the open end will naturally lie in an inclined plane. The open end of the bag is secured to ring I2 in any suitable manner, as by placing the ring inside the open mouth o f the bag and tieing a string or cord 29 therearound. A bag :made in this manner tapers from either end toward the intermediate point of smallest diameter.

The other end of casing lis provided with a ring 30 within which is suitably supported a motor-fan unit comprising an electric motor 3i, having impellers 32 mounted on the motor shaft, and a fan housing 33 surrounding the impellers. The forward wall of this housing 33 is provided with a fan inlet opening 33. Secured to this forward wall is a coil spring 35, to the other end of which is fastened a perforated plate 36 having dimensions somewhat less than the: interior dimensions of casing iIl. The length of dust bag 32 is such that the closed end of the bag bears against plate 36 and, even with the plate in a position with spring 35 completely compressed, the sides of the bag are folded.

Mounted within the upper part of casing I3 is a bracket 31, slidably supporting a bar 3B. One end of the bar 38 is bent at right angles and extends behind plate 33 so that movement of the plateI to the right, as viewed in Fig. 1, causes corresponding movement of bar 38. A coil spring 39 is placed between bracket 31 and a nange 4I) on bar-38 and tends to move the bar toward the left. A portion 4I of bar 38 moves underneath an airtight window 42. The right-hand half of portion 4I may be painted white and the lefthand half red, or the portion may be marked in some other manner so that observation of it through window 42 will enable the operator to note its position.

A cap member 43 is secured to ring 30 in any suitable manner, such as by spring clips 44, and serves to enclose the rear end of motor 3l. 43 is provided with a threaded outlet opening 45, into which coupling I8 may be screwed if it is desired to employ the device as a blower. A housing 46 encloses an electric switch and electric contacts, to which the plug of an electric cord may be attached. A handle 4l serves as a convenient means for carrying the cleaner. A pair of runners 48 are secured at opposite ends to rings II and-30 respectively, and serve to movably support the vacuum cleaner on a surface, such as a oor.

In order to assure that the dust bag is placed in the casing with the seam 28 at the top, flange I3 of dust bag ring I2 may be formed with a pro- Cap jection S@ adapted to engage a depression 5I in the face of ring il. Hence, cover l5 cannot be clamped in place unless the bag is in the proper position.

The operation of the above described device is as follows:

Rotation of the impellers 32 by the motor 3l causes a current of air to be drawn in through nozzle 23, handle 2l, hose I9 and the coupling I8, into dust bag 22. If nozzle 20 is passed over a dusty surface, this current of air bears entrained dust. This dust is deposited within dust bag 22, while the air passes through the material of the dust bag to the fan, from which it is discharged throughi and around motor 3l to the outlet t5.

The material of the dust bag always oiers some resistance to the flow of air therethrough and hence the pressure of the air outside `of the bag is lower than the pressure inside. This tends to inflate the bag to the fullest extent. inasmuch as the length of the bag is somewhat greater than the distance between dust bag ring I2 and the movable plate 36, the bag, on becoming inflated, tends to move the plate 38 to the right, as viewed in Fig. l. The strength of spring 35 is so selected that the force exerted by the bag when the latter is clean and hence offers the minimum resistance to the passage of air therethrough, is not sufficient to rnove the plate an appreciable distance. However, as dirt accumulates within the bag it increases the resistance to flow of air therethrough and hence the pressure difference between the inside and outside of thev bag becomes greater and the bag exerts a greater force against the plate 3E. This moves the plate to the right against the force of spring 35 and this movement is communicated to bar 38. When suicient dust has accumulated to require the emptying of the bag, bar 38 has been moved to the right suiciently so that the red part thereof is visible to the operator through window ft2. This indicates to the operator that the bag should be removed and emptied. To do this, it is only necessary to release spring clips I6 and remove the cover member I5. When this is done, theA dirt which has accumulated within the bag will not have the tendency to fall out through the openmouth, inasmuch as the opening is in an inclined plane.l 'Ihe bag may be removed by grasping ringv I2 and the contents may be disposed of in any suitable place.

In order to insert the bag, the motor-fan unit is started and the closed end of the bag placed within the inclined opening with seam 28 at the top. The inowing air acts on the bag and tends to draw it into the casing, and at the same time inates the bag. As before stated, if the bag were cylindrical, the inilation would straighten out the bag and the lower closed end thereof would strike the bottom of the casing, inasmuch as the bag is naturally held in an inclined position in order to insert it through the inclined opening. However, because of the shape of the bag, ination thereof does not tend to make it assume a straight position, but tends to raise the closed end of the bag so that it will not bear against the bottom of the casing. Consequently, the bag will be drawn into the casing until the closed end strikes plate 38; Thereafter, due to its excess length, the sides of the bag will be folded as shown in Fig. 1.

Another advantage resulting from a bag of this shape, whether it is used in a casing having an inclined opening or an opening in a vertical plane, is that the folds caused by an excess length $15 of the bag tend to take place toward the closed end. I have discovered that with a truly cylindrical bag these folds have a tendency to occur adjacent the mouth of the bag and, if the opening is in an inclined plane particularly where the axis changes from an inclined to a horizontal direction. If the folds take place nearthe mouth of the bag they tend to reduce the size of the passage through the bag and a large amount of dirt is deposited near the mouth. Due, however, to the reduced diameter of the bag a short distance from its mouth, the tendency of the bag to inate straightens the walls of the bag at this place and causes the folds to take place more toward the closed end of the bag.

In the above it has been assumed that the motor-fan unit is started before the .bag is inserted through the opening. However, if desired, the bag may be placed in first, in which case it will be very much folded adjacent to the mouth.

Thereafter, when the motor-fan unit is started the flow of air inates the bag and causes the folds and the closed end to move toward the rear in the same manner as previously'explained.

While I have shown and described but one more or less specic embodiment of my invention, this has been done for purposes of illustration only and the scope of my invention is not to be limited thereby but is to be determined by the appended claims viewed in the light of the prior art.

What I claim is:

1. In a vacuum cleaner, a casing defining an elongated dust bag space, said casing being formed with an opening at one end of said space for the insertion therethrough of a dust bag-the plane of said opening being inclined with respect to the lengthwise extent of said space, means for producing W of air through said space, an elongated. dust bag adapted to be received in said space, said bag having an open mouth at one end and being closed at the other end, and means for securing the open end in the plane of the opening in the casing, the diameter of said bag being less at an intermediate point than at either end.

2. In a vacuum cleaner, a casing defining an elongated dust bag space, said casing being formed with an opening at one end of said space for the insertion therethrough of a dust bag, means for producing flow of air through said space, a dust bag of greater length than said space adapted to be received in said space in folded condition, said bag having an open mouth at one end and being closed at the other end, and means for securing said open end to said casing, the cross-sectional area of said bag being less at an intermediate point than at points at either side of said intermediate point.

mediate point.

4. In a vacuum cleaner of the class having a casing forming a dust bag space and provided with means for producing flow of air therethrough, the combination with said casing of an elongated dust bag having an open mouth at one end and being closed -at all other places, the cross-sectional area of said bag being less at an intermediate point than at points at either side of said intermediate point.

GUSTAF EINAR LOFGREN. 4 

